Rational Function (MATLAB)

[47box]

Hi,

I´ve been trying to plot a rational function to see the graph of it.

f(x) = (2x⁴-x²+1) / x²-4


From a book I´m following a graph is showed below :

figure1


I created a script trying make a graph comes out.

clear
clc

x =(-100:0.01:100);
y = ((2.*(x.^4))-(x.^2)+1)./(x.^2)-4;
plot(x,y),hold on
axis([-4 4 -50 50])
grid on

I got a graph completely out of what we have in a image above from the book.



As we can see it pass the limits of -2 and 2.
How can I plot a graph and have the same as we have in the book (figure 1)?
I tried to see matlab materials and could not figure out how to do that.

Thanks in advance

 

[pancho_hideboo]

Simply your denominator is wrong in coding.
Surely confirm parenthesis.

y = (2*x.^4-x.^2+1)./(x.^2-4);

 

[47box]

That is it. Thank you.